scholarly journals Jet and counter-jet in transonic pulsar wind nebulae

2021 ◽  
Vol 2103 (1) ◽  
pp. 012021
Author(s):  
G A Ponomaryov ◽  
K P Levenfish ◽  
A E Petrov
Keyword(s):  
Relative Motion ◽  
Rest Frame ◽  
Pulsar Wind Nebulae ◽  
Reverse Shock ◽  
X Ray ◽  
Pulsar Wind ◽  
Mhd Model ◽  
Double Torus

Abstract X-ray observations show that a jet and a counter-jet in pulsar wind nebulae often differ one from another. Sometimes one of the jets is not observed at all. We show that the most likely reason for this difference is the relative motion of a pulsar and an ambient matter. Even the slow (subsonic or transonic) ambient matter stream in the pulsar rest frame strongly affects the jets, making the windward jet bright and dynamic, and the leeward jet dim and diffuse. The effect is illustrated using a relativistic MHD model of a double-torus pulsar wind nebula. The model is shown to explain reasonably well the observational appearance of the jets in the Vela nebula - a double-torus object which evolves in a transonic stream initiated by the passage of the reverse shock of the parent supernova.

scholarly journals Slow motion pulsar wind nebulae

2021 ◽  
Vol 2103 (1) ◽  
pp. 012020
Author(s):  
K P Levenfish ◽  
G A Ponomaryov ◽  
A E Petrov ◽  
A M Bykov ◽  
A M Krassilchtchikov
Keyword(s):  
Time Scales ◽  
Relative Motion ◽  
Slow Motion ◽  
High Energy ◽  
Pulsar Wind Nebulae ◽  
Extra Time ◽  
X Ray ◽  
Energy Emission ◽  
Pulsar Wind ◽  
High Energy Emission

Abstract We show that even the slow (subsonic) motion of pulsar wind nebulae (PWNe) relative to an ambient matter has a significant impact on their observables. The motion changes the appearance of nebulae on X-ray images, comparing to what would be observed for a nebula at rest. Accounting for the relative motion is necessary to avoid misinterpretation of the structure of the nebulae when analyzing their X-ray morphology. The motion also introduces some extra time scales in variability of non-thermal high-energy emission of PWNe and allows to reproduce a number of their structures that are not explained by stationary nebula models.

scholarly journals Deciphering the nature of the pulsar wind nebula CTB 87 with XMM–Newton

2019 ◽  
Vol 491 (2) ◽  
pp. 3013-3021 ◽  
Author(s):  
B Guest ◽  
S Safi-Harb ◽  
A MacMaster ◽  
R Kothes ◽  
B Olmi ◽  
...  
Keyword(s):  
Supernova Remnant ◽  
Thermal Emission ◽  
Plasma Temperature ◽  
Evolutionary Stage ◽  
Reverse Shock ◽  
X Ray ◽  
Upper Limit ◽  
Supernova Shell ◽  
Pulsar Wind ◽  
Hydrodynamical Simulations

ABSTRACT CTB 87 (G74.9+1.2) is an evolved supernova remnant (SNR) which hosts a peculiar pulsar wind nebula (PWN). The X-ray peak is offset from that observed in radio and lies towards the edge of the radio nebula. The putative pulsar, CXOU J201609.2+371110, was first resolved with Chandra and is surrounded by a compact and a more extended X-ray nebula. Here, we use a deep XMM–Newton observation to examine the morphology and evolutionary stage of the PWN and to search for thermal emission expected from a supernova shell or reverse shock interaction with supernova ejecta. We do not find evidence of thermal X-ray emission from the SNR and place an upper limit on the electron density of 0.05 cm−3 for a plasma temperature kT ∼ 0.8 keV. The morphology and spectral properties are consistent with a ∼20-kyr-old relic PWN expanding into a stellar wind-blown bubble. We also present the first X-ray spectral index map from the PWN and show that we can reproduce its morphology by means of 2D axisymmetric relativistic hydrodynamical simulations.

scholarly journals Peculiar Differences in Radio and X-ray Synchrotron Radiation from Pulsar Wind Nebulae

2004 ◽  
Vol 218 ◽  
pp. 221-224
Author(s):  
John R. Dickel ◽  
Shiya Wang
Keyword(s):  
Synchrotron Radiation ◽  
Radio Emission ◽  
Supernova Remnants ◽  
Crab Nebula ◽  
Pulsar Wind Nebulae ◽  
X Ray ◽  
Pulsar Wind ◽  
The Crab Nebula

Several Crab-type supernova remnants appear to have very bright non-thermal X-ray cores just around the pulsar or expected pulsar. This X-ray brightness is often not matched by a corresponding increase in radio emission. The best example of this phenomenon is in N157B in the LMC. G21.5−0.9 and possibly 3C 58 also show it while the Crab Nebula and 0540−69.3 do not. Some method to enhance the higher energy particles must be present in these objects.

scholarly journals Jet-like structures from PSR J1135–6055

2020 ◽  
Vol 644 ◽  
pp. L4
Author(s):  
P. Bordas ◽  
X. Zhang
Keyword(s):  
High Energy ◽  
Bow Shock ◽  
Morphological Properties ◽  
Physical Origin ◽  
Pulsar Wind Nebulae ◽  
Jet Formation ◽  
X Ray ◽  
Pulsar Wind ◽  
Alternative Scenarios ◽  
High Energy Particles

Pulsar wind nebulae (PWNe) produced from supersonic runaway pulsars can render extended X-ray structures in the form of tails and prominent jets. In this Letter, we report on the analysis of ∼130 ks observations of the PWN around PSR J1135–6055 that were obtained with the Chandra satellite. The system displays bipolar jet-like structures of uncertain origin, a compact nebula around the pulsar likely formed by the bow shock ahead of it, and a trailing tail produced by the pulsar fast proper motion. The spectral and morphological properties of these structures reveal strong similarities with the PWNe in other runaway pulsars, such as PSR J1509–5850 and Geminga. We discuss their physical origin considering both canonical PWN and jet formation models as well as alternative scenarios that can also yield extended jet-like features following the escape of high-energy particles into the ambient magnetic field.

scholarly journals Revealing hidden variability in PWNe with spectral index maps

2020 ◽  
Vol 498 (1) ◽  
pp. 821-834
Author(s):  
Benson T Guest ◽  
Samar Safi-Harb
Keyword(s):  
Spectral Index ◽  
Rotational Energy ◽  
Line Of Sight ◽  
Pulsar Wind Nebulae ◽  
X Ray ◽  
Analysis Technique ◽  
Intrinsic Motion ◽  
Pulsar Wind ◽  
Map Analysis ◽  
Index Maps

ABSTRACT Pulsar wind nebulae (PWNe) are the synchrotron bubbles inflated by the rotational energy of a neutron star. Observing variability within them has previously been limited to cases of significant brightening, or the few instances where transient features are interpreted in terms of intrinsic motion or associated with variability from the pulsar. Jet and torus morphology are also only visible in cases of differing brightness with respect to the surrounding nebula and favourable alignment with our line of sight. Spectral map analysis involves binning observations with an adaptive algorithm to meet a signal limit and colouring the results based on the desired model parameter fits. Minute changes in spectral index become therefore apparent even in cases where brightness images alone do not suggest any underlying changes. We present a Chandra X-ray study of the PWNe in G21.5–0.9, Kes 75, G54.1+0.3, G11.2–0.3, and 3C 58, using archival observations accumulated over the ∼20-yr lifetime of the mission. With the spectral map analysis technique, we discover evidence for previously unknown variability opening a new window into viewing PWNe.

scholarly journals Searching for X-ray counterparts of Fermi Gamma-ray pulsars in Suzaku observations

2011 ◽  
Vol 7 (S279) ◽  
pp. 317-318 ◽  
Author(s):  
Yu Aoki ◽  
Takahiro Enomoto ◽  
Yoichi Yatsu ◽  
Nobuyuki Kawai ◽  
Takeshi Nakamori ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Thermal Emission ◽  
Flux Ratio ◽  
Radio Pulsars ◽  
Pulsar Wind Nebulae ◽  
X Ray ◽  
Absorbed Power ◽  
Pulsar Wind ◽  
Error Circle

AbstractWe report the Suzaku follow-up observations of the Gamma-ray pulsars, 1FGL J0614,13328, J1044.55737, J1741.82101, and J1813.31246, which were discovered by the Fermi Gamma-ray observatory. Analysing Suzaku/XIS data, we detected X-ray counterparts of these pulsars in the Fermi error circle and interpreted their spectra with absorbed power-law functions. These results indicate that the origin of these X-ray sources is non-thermal emission from the pulsars or from Pulsar Wind Nebulae (PWNe) surrounding them. Moreover we found that J1741.82101 exhibits a peculiar profile: spin-down luminosity vs flux ratio between X- and gamma-rays is unusually large compared to usual radio pulsars.

scholarly journals Reverberation of pulsar wind nebulae (I): impact of the medium properties and other parameters upon the extent of the compression

2020 ◽  
Vol 499 (2) ◽  
pp. 2051-2062 ◽  
Author(s):  
R Bandiera ◽  
N Bucciantini ◽  
J Martín ◽  
B Olmi ◽  
D F Torres
Keyword(s):  
Ambient Medium ◽  
Crab Nebula ◽  
Late Phase ◽  
Pulsar Wind Nebulae ◽  
Reverse Shock ◽  
Pressure Profiles ◽  
Pulsar Wind ◽  
Radiation Processes ◽  
The Crab Nebula

ABSTRACT The standard approach to the long-term evolution of pulsar wind nebulae (PWNe) is based on one-zone models treating the nebula as a uniform system. In particular for the late phase of evolved systems, many of the generally used prescriptions are based on educated guesses for which a proper assessment lacks. Using an advanced radiative code, we evaluate the systematic impact of various parameters, like the properties of the supernova ejecta, of the inner pulsar, as well of the ambient medium, upon the extent of the reverberation phase of PWNe. We investigate how different prescriptions shift the starting time of the reverberation phase, how this affects the amount of the compression, and how much of this can be ascribable to the radiation processes. Some critical aspects are the description of the reverse shock evolution, the efficiency by which at later times material from the ejecta accretes on to the swept-up shell around the PWN, and finally the density, velocity, and pressure profiles in the surrounding supernova remnant. We have explicitly treated the cases of the Crab Nebula, and of J1834.9−0846, taken to be representatives of the more and the less energetic pulsars, respectively. Especially for the latter object, the prediction of large compression factors is confirmed, even larger in the presence of radiative losses, also confirming our former prediction of periods of superefficiency during the reverberation phase of some PWNe.

scholarly journals Pulsar Wind Nebulae and the X‐Ray Emission of Nonaccreting Neutron Stars

2004 ◽  
Vol 617 (1) ◽  
pp. 480-489 ◽  
Author(s):  
K. S. Cheng ◽  
Ronald E. Taam ◽  
W. Wang
Keyword(s):  
Neutron Stars ◽  
Pulsar Wind Nebulae ◽  
X Ray ◽  
Pulsar Wind

scholarly journals PULSAR WIND NEBULAE MODELING

2014 ◽  
Vol 28 ◽  
pp. 1460162 ◽  
Author(s):  
NICCOLÒ BUCCIANTINI
Keyword(s):  
High Resolution ◽  
High Energy ◽  
Clear Understanding ◽  
Strong Impact ◽  
Pulsar Magnetosphere ◽  
Pulsar Wind Nebulae ◽  
X Ray ◽  
X Ray Imaging ◽  
Dynamical Properties ◽  
Pulsar Wind

Pulsar Wind Nebulae (PWNe) are ideal astrophysical laboratories where high energy relativistic phenomena can be investigated. They are close, well resolved in our observations, and the knowledge derived in their study has a strong impact in many other fields, from AGNs to GRBs. Yet there are still unresolved issues, that prevent us from a full clear understanding of these objects. The lucky combination of high resolution X-ray imaging and numerical codes to handle the outflow and dynamical properties of relativistic MHD, has opened a new avenue of investigation that has lead to interesting progresses in the last years. Despite all of this, we do not understand yet how particles are accelerated, and the functioning of the pulsar wind and pulsar magnetosphere, that power PWNe. I will review what is now commonly known as the MHD paradigm, and in particular I will focus on various approaches that have been and are currently used to model these systems. For each I will highlight its advantages, limitations, and degree of applicability.

scholarly journals Constraining the geometry of PSR J0855−4644: A nearby pulsar wind nebula with double torus/jet morphology

2017 ◽  
Vol 597 ◽  
pp. A75 ◽  
Author(s):  
C. Maitra ◽  
F. Acero ◽  
C. Venter
Keyword(s):  
Light Curve ◽  
Spatial Modelling ◽  
Beam Model ◽  
X Rays ◽  
X Ray ◽  
Compact Source ◽  
Pulsar Wind ◽  
Double Torus ◽  
Gap Models

Aims. PSR J0855−4644 is a fast-spinning, energetic pulsar discovered at radio wavelengths near the south-eastern rim of the supernova remnant RX J0852.0−4622. A follow-up XMM-Newton observation revealed the X-ray counterpart of the pulsar and a slightly asymmetric pulsar wind nebula, which suggests possible jet structures. Lying at a distance d ≤ 900 pc, PSR J0855−4644 is a pulsar with one of the highest Ė/d2 from which no GeV γ-ray pulsations have been detected. With a dedicated Chandra observation we aim to further resolve the possible jet structures of the nebula and study the pulsar geometry to understand the lack of γ-ray pulsations. Methods. We performed detailed spatial modelling to constrain the geometry of the pulsar wind nebula and in particular the pulsar line of sight (observer angle) ζPSR, which is defined as the angle between the direction of the observer and the pulsar spin axis. We also performed geometric radio and γ-ray light-curve modelling using a hollow-cone radio beam model together with two-pole caustic and outer gap models to further constrain ζPSR and the magnetic obliquity α defined as the angle between the magnetic and spin axes of the pulsar. Results. The Chandra observation reveals that the compact XMM source, thought to be the X-ray pulsar, can be further resolved into a point source surrounded by an elongated axisymmetric nebula with a longitudinal extent of 10′′. The pulsar flux represents only ~1% of the XMM compact source, and its spectrum is well described by a blackbody of temperature kT = 0.2 keV, while the surrounding nebula has a much harder spectrum (Γ = 1.1 for a power-law model). Assuming the origin of the extended emission is a double torus yields ζPSR = 32.5° ± 4.3°. The detection of thermal X-rays from the pulsar may point to a low value of | ζ−α | if this emission originates from a heated polar cap. Independent constraints from geometric light-curve modelling yield α ≲ 55° and ζ ≲ 55°, and 10° ≲ | ζ−α | ≲ 30°. A χ2 fit to the radio light curve yields a best fit at (α,ζPSR) = (22°,8°), with an alternative fit at (α,ζPSR) = (9°,25°) within 3σ. The lack of non-thermal X-ray emission from the pulsar further supports low values for α and ζ under the assumption that X-rays and γ-rays are generated in the same region of the pulsar magnetosphere. Such a geometry would explain, in the standard caustic pulsar model picture, the radio-loud and γ-ray-quiet behaviour of this high Ė/d2 pulsar.

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